Use of immunohistochemestry to search prion protein in third eyelid of sheep in Chile

Abstract

An immunohistochemstry (IHC) method to detect scrapie in sheep third eyelid lymphoid tissue was applied in post mortem animals. This method would allow to carry out the diagnosis in Chile, including the preclinical phase of the disease in sheep flock. Eighty samples from two year old sheep were obtained. Fourty two showed neurological signs consistent with scrapie and thirty eight came from slaughterhouse. Another thirteen blind samples were provided by a Reference Center (RC) in addition to sixteen obex used as controls. Samples were evaluated in sections with hematoxilin-eosin and classified as suitable if presenting at least four lymphoid follicles in the tissue. Based on this, seventy four out of ninety samples were considered suitable. The IHC results showed that all samples were negative to scrapie and only seven provided by the RC were positive. All obex samples were positive to immunostaining by PrP^Sc, unlike negative controls. The results demosntrate that this diagnostic tool may be considered for monitoring the sanitary condition related to scrapie in the ovine flock in Chile.